Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add alivirgo/Major-AI-Skills --skill compact-yaml-frontmattergit clone --depth 1 https://github.com/alivirgo/Major-AI-SkillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/alivirgo/major-ai-skills/compact-yaml-frontmatter)<a href="https://agentmods.dev/skills/alivirgo/major-ai-skills/compact-yaml-frontmatter"><img src="https://agentmods.dev/badge/skills/alivirgo/major-ai-skills/compact-yaml-frontmatter/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/alivirgo/major-ai-skills/compact-yaml-frontmatter"><img src="https://agentmods.dev/badge/skills/alivirgo/major-ai-skills/compact-yaml-frontmatter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00025 | $0.01093 |
| Opus 5 | $0.00013 | $0.00547 |
| Sonnet 5 | $0.00005 | $0.00219 |
| Haiku 4.5 | $0.00003 | $0.00109 |
Grade A, and why
compact-yaml-frontmatter scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Compact YAML Frontmatter & Knowledge Metadata
Overview
In automated knowledge management, RAG documentation suites, and AI skill repositories, every Markdown file starts with a YAML frontmatter block (--- ... ---).
Unoptimized frontmatter blocks frequently accumulate 15 to 25 lines of redundant metadata (author emails, redundant timestamps, verbose SEO keyword paragraphs, placeholder schemas), consuming 150 to 300 tokens per file. When a RAG retrieval system fetches 10 documents, the agent burns 2,500 tokens purely on metadata headers before reading any actual content.
The Compact YAML Frontmatter Protocol enforces a Lean 3-to-4 Field Standard, delivering maximum indexing signal with minimal token footprint.
Bloated Metadata vs. Lean High-Density Frontmatter
┌─────────────────────────────────────────────────────────────┐
│ Frontmatter Token Comparison │
│ │
│ Bloated YAML Frontmatter (240 Tokens per Doc): │
│ --- │
│ title: "Comprehensive Guide to Distributed Caching" │
│ author: "Engineering Architecture Working Group" │
│ created_at: "2026-08-22T17:55:00.000Z" │
│ updated_at: "2026-08-22T17:55:00.000Z" │
│ keywords: ["cache", "redis", "distributed", "caching"...] │
│ category: "Backend Systems Architecture Documentation" │
│ version: "1.0.4-beta.2" │
│ description: "This comprehensive document provides an..." │
│ --- │
│ ↳ 240 tokens billed per document fetched │
│ │
│ Lean Compact Frontmatter (42 Tokens - 82.5% Reduction): │
│ --- │
│ title: "Distributed Caching (Redis/Memcached)" │
│ description: "Architecture guide for cache eviction..." │
│ tags: ["redis", "caching", "architecture"] │
│ --- │
│ ↳ 42 clean tokens, 100% search & retrieval fidelity │
└─────────────────────────────────────────────────────────────┘
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday Changed · -12 tokens per session fa36553db507
- 7d ago First seen · 97 lines · 37 tokens per session scan A 3fe8c95ab762
compact-yaml-frontmatter is a skill published in the GitHub repository alivirgo/Major-AI-Skills (1 stars, last pushed today), licensed MIT. It adds 25 tokens to every session and 1,093 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-05.
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